They are intended to accelerate a small projectile at high speed using combustion gases as the prime mover.

I don't want to turn this into a political flamewar, but please don't assume malicious intent as the primary motivation for a tool's existence. That's like saying lockpicks are only good for burglary, axes for dismemberment, or knives for stabbing.

Non-violent guns: https://www.navalcompany.com line throwing shotgun

https://en.m.wikipedia.org/wiki/Flare_gun Flare gun

And blanks are used to sink things in concrete.

It's a tool. It has a function. The function of the tool is independent of the intents of it's wielder.

Thanks. Why does it get you?

Is it different from martial arts people who are eloquent and informed about swords?

It always gets me how emotional and rabid do-gooder people become about owning weapons which are basically tools which have many legitimate uses.